The goal of Core D: Imaging and Physiology Core, is to provide technical support, expertise, and resources for electron microscopy, fluorescence &confocal microscopy, image analysis, and mouse lung vascular permeability measurements that will be required to address the specific aims of all projects. The centralization of the imaging and physiological support within Core D is necessitated by the emphasis of the individual projects on the physiological relevance of the proposed studies. Thus, Core D will provide equipment and technical expertise for carrying out and analyzing the functional studies in mouse lungs or endothelial cell monolayers. In this context, Core D will provide expertise and technical support for studying the permeability of lung vascular endothelial barrier using physiological methods (i.e., pulmonary microvessel filtration coefficient and vessel wall albumin permeability surface area product) as well as examination of specific permeability pathways using electron microscopy and quantitative image analysis at the level of cell-cell junctions and transcellular pathway. All Projects will require assessments of lung vascular permeability provided by Core D. Core D will also provide expertise for the formulation of DNA containing cationic liposomes and the transfection of genes of interest in mouse lung microvessels. Core D personnel, who have extensive training and experience in the described procedures, will provide the support and resources outlined below as well as the necessary training of personnel in all Projects.